Piston-head packing for rock-drills



(NoModeLl L. s. WOODBURY. v

PISTON HEAD PACKING FOR. ROCK DRIL'LSL No. 320,829.

PatentedJune 23, 1885.

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UNITED STATES PATENT OFFICE.

LEANDER S. VVOODBURY, OF CALUMET, MICHIGAN.

PISTON-HEAD PACKING FOR ROCK-DRILLS.

SPECIFICATION forming part of Letters Patent No. 320,829, dated June 23, 1885.

Application filed January 12, 1885.

T 0 all whont it may concern:

Be it known that I, LEANDER S. ODD- BURY, a citizen of the United States, residing at Calumet, in the county of Houghton and State of Michigan, have invented a new and useful Improvement in Piston-Head Packing for Rock-Drills, set forth in the annexed specification.

My invention relates to that class of pack ing which is held against the cylinder by the pressure used within the cylinder; and it has for its objects, first, to secure an absolutelytight packing, that can be cheaply made, and can be easily and quickly replaced, when worn out, by the one who uses the drill; second, to avoid the derangements common to the metallic packing usually used in rock-drills. These objects are accomplished in the device illus trated in the accompanying drawings, in Which Figure 1 is a central longitudinal section of a portion of the cylinder, cylinder-head, piston-head, and packing, the piston-r0d being shown in elevation. Fig. 2 is a plan of rings P and 0, looking from the bottom. Fig. 3 is a side elevation of ring P, to show the method of splitting the same when desired.

Si milar letters refer to similar parts throughout the views, in which A is the cylinder. B is' the cylinder-head. S is a packing in cylinder-head to prevent escape of pressure around -the rod 0. P is acup-shaped ring, made of,

some yielding material-as compressed leather, compressed'or vulcanized fiber, rawhide,

8w; 0 is a ring of elastic rubber,for the purpose of holding the packing-ring P in place and for other purposes hereinafter specified. D is the piston-head. x 00, Figs. 2 and 3, show, the method of splitting ring P, for the purpose hereinafter specified.

Having thus described the parts, I will proceed to describe their operation and use.

In rock-drills the drill striking the rock is supposed to limit the stroke, so that the pistonhead will not strike the cylinder-head; but when from any cause-such as a broken drill or improper feeding-the piston-head would otherwise strike the cylinder, the piston-head is supposed to cushion upon the air remaining in the cylinder; but to get an effective cushion an absolute confinement of the air is necessary,

(No model.)

and to this end a perfectly-tight packing is required around the rod and in the piston-head.

The packing heretofore used in rock-drills is metallic, being a simple ring out in halves, so that it can be let into the groove in the piston, the nature of the work of a rock-drill being such as to require that the piston-head itself should be in one piece.

It is well known that most cylinders in which a metallic packing is used are worn tapering, being the largest at the ends. They are also often worn out of round, or become out or scored. These derangements are especially peculiar to rock-drills-first, because of the lateral strain that often comes upon the piston and piston-head; second, because of the dust and grit peculiar to mining operations being carried into the cylinder in the air; and, third, because where air is used it has no lubricating qualities, as is the case with saturated steam. Now, a metallic packing suitable to withstand the shock and jar incident to this class of machines will not accommodate itself to the inequalities above mentioned, and a leakage takes place, especially at the ends, where the most perfect confinement is required.

Referring now to Fig. 1 of the drawings, it will be seen that whenever there is any pressure in the cylinder, either by admission or compression, it keeps the ring P against the cy1- inder, efiectually shutting off all escape of pressure in that direction, and as this packing readily accommodates itself to any inequalities in the cylinder, perfect tightness is maintained throughout the stroke.

The method of holding the packing P in place constitutes the peculiarity of the packing. When the drill is working properly, it strikes the rock with great force and rapidity, stopping the piston-head suddenly before any compression of air is formed in the cylinder, and the ring 1? is thrown forward with considerable force. packing P is let into a simple groove in the piston-head, so that when it is thrown forward its thrust comes upon the solid metal, the flat part is very soon worn away or torn off, and the packing becomes worthless. To prevent this is the peculiar office of the ring 0, which is made of elastic rubber. This ring is normally smaller than the piston, around which When the flat part F of the it is stretched; but itis of such a size that when stretched and crowded into place it is h eld ti ghtl y around the piston-head, but allows thepacking-riug P to move freely around it. N ow, when the piston-head is suddenly stopped by the impact of the drill upon the rock, the rubber ring 0 takes the thrust of the packingring P, yielding somewhat to it, and little or no wear comes upon the flat part F, as before. When the whole drill is assembled in the shop, before sending it into the mine for duty, the packing-ring is put into the piston-head without splitting it in the following manner: It is forced over the end of the piston-head, which. is rounded for that purpose. The rubber ring 0 is then rubbed over with plumbago, after which it is easily crowded into place. When by use the packing-ring P becomes worn and needs replacing, the head 13 is loosened and the piston drawn out, when, by detaching the rod from the pistonhead, the packingring P may be renewed by the same process, and on the upper end of the piston-head the packing is put on and renewed in the same way. It is not, however, considered advisable to detach the rod in the mine, so to enable the user of the drill to renew he packing P without detaching the rod he packing may be split, as shown by lines'x 00, Figs. 2 and 3. It may then be sprung round the piston-head, and the rubber ring 0 put in place, as before, when,

the piston-head being slipped back into the cylinder and the cylinder-head fastened, the drill is again ready for use. There is one other derangement peculiar to the metallic packing.

, Bytheshock of the impact of the drill the metallic packing, having an inertia six to eight times that of a fibrous packing, soon becomes loose by the constant hammering upon the side of the groove, causing a leakage around the ring, and the ring is frequently broken, when the drill becomes useless until repairs are made.

None of the foregoing derangements incident to the metallic packing are likely to occur with thefibrous packing-first, because the packing will wear in preference to the cylinderfsecond, by reason of its fibrous nature the packing P will retain any lubricant applied to it, and the cylinder becomes moreperfectly lubricated.

I make no broad claim upon a fibrous cupshaped packing, simply as such.

I claim no necessity fOl@ 11OV6lty in splitting the packing so as to make a lap-joint.

What I do claim as new,and desire to secure by Letters Patent, is-

The combination, in the piston-head of a rock-drill, of the fibrous cup-shaped packingring P, formed substantially as shown, with the piston-head D, formed as shown, so that the packing-ring can be pressedinto the groove of the same, as set forth, and the elastic ring 0, so made as to fill the space in the groove not taken up by the packing-ring, and serving to hold the packing-ring in place, and also as an elastic cushion for any lateral thrust of the packing-ring against it, all substantially as and for the purposes herein set forth.

LEANDER S. VVOODBURY.

\Vitnesses:

F. G. OOGGIN, J AS. M. MERroN.

It is hereby certified that in Letters Patent No. 320,829, granted June 23, 1885, upon the application of Leander S. Woodbury, of Calumet, Michigan, for an improvement in "Piston-Head Packing for Rock-Drills, errors appear in the printed specification requiring the following correction In line 26, page 2, the word as should be omitted; in line 28, same page, the period after the word rod should be omitted, a comma read in place thereof, and the following word The read the, thus making the sentence continuous; in line 54, same page, the article a. should be read or; and that the Letters Patent should be read with these corrections therein to make it conform to the records of the case in the Patent Office.

Signed, countersigned, and sealed this 4th day of August, A. D. 1885.

[SEAL-1 e. A. JENKS,

Acting Secretary of the Interior. Oountersigned M. V MONTGOMERY,

Commissioner of Patents. 

